Nadal played at the Vina del Mar Open in Chile earlier this month, losing the singles and doubles finals last Sunday.

But 11-time grand slam winner is hopeful that he's back on the right path following a torrid time with injury.

He added: "I just need time to continue improving and return to a more competitive level."

Since last June's shock second round exit at Wimbledon, Nadal has suffered with a torn tendon and an inflammation of his left knee.

Nadal was forced to miss the Olympics and U.S Open as he continued his battle for full fitness.

His return was then further delayed by a stomach virus, forcing him to withdraw from the Australian Open.

Meanwhile, Milos Raonic confirmed his as the king of the indoor hard court at the SAP Open, winning the San Jose event for the third year in a row.

The Canadian beat German Tommy Haas 6-4 6-3 in Sunday's final, taking winning streak at the event to 12 matches.

The world No. 13 has won all 24 sets he has played during his three title-winning campaigns.

"It's pretty awesome. It's pretty special," the 22-year-old Raonic told the ATP World Tour's official website. "It's more than just the trophies that I have. It's the little things that come with it.

"There was always the maple syrup story. The San Jose Sharks jersey. It all means a lot. With this event, that has had so many great champions, it's pretty special. To sort of one-up it and three-peat is pretty awesome."